1. Field of the Invention
The invention relates to image processing, and more particularly to a method for detecting multiple image areas in a digital image.
2. Description of the Related Art
With the advent of digital cameras and scanners, digital photography is becoming more popular and accessible to consumers. Digital images are often created either by capturing a scene using a digital camera or digitizing a traditional film-based photograph using a scanner. Digital photography has many advantages over the traditional film-based photography. One particular advantage is that digital images can be easily manipulated or edited for better presentation. Furthermore, the digital images can be readily distributed over electronic media such as the internet or electronic mail.
When a scanner is used to create a digital image from a film-based photograph, often the user has to scan in each photograph separately because most scanners treat each scan page as one picture. If multiple photographs are scanned in at the same time, the entire scan page is treated as one image and individual photographs cannot be readily separated into individual image files. Because the scan process can be very slow, often up to a few minutes per scan page, it is very time consuming to scan a large number of photographs individually. Because film-based photographs are usually 3″ by 5″ or 4″ by 6″ and because the scan page is typically large enough to accommodate more than one such photographs, it is desirable to scan multiple photographs at a time to speed up the scanning process.
Presently, when a scanned image is created including multiple photographs, the individual photographs can be extracted using commonly available photo editing tools. Often, the process requires the user to manually extract each photograph from the scanned image to generate separate image files for each individual photograph. Such manual cropping may be a complicated and time consuming process in itself. Furthermore, most photo editing tools may limit the crop area to a certain shape, such as an upright rectangular binding box. In that case, the user must ensure that the photographs are aligned properly on the scanner before scanning so that individual photographs will fit properly inside the cropping rectangle.
A scanner with batch scan capability allowing the user to scan multiple images in one scan job has been introduced. It is desirable to provide a method for automatically detecting and extracting individual photographs from a digital image containing multiple photographs. Such algorithm should be able to perform such automatic detection effectively so that manual intervention is entirely eliminated.